1. Field of the Invention
This invention pertains to the detection of analyte through the monitoring of induced electron motion in conducting elements. The present invention is an improvement of the inventions disclosed in pending U.S. patent application Ser. No. 09/110,686, now U.S. Pat. No. 6,096,497, which is herein incorporated by reference, and PCT application PCT/IL99/00309. The present invention describes in greater detail a method and device for detecting induced base member electron motions responsive to analyte presence.
2. Description of the Related Art
In the aforementioned patent applications, a sensor for analyte detection is described. The sensor is very sensitive, quick in response, easy to prepare, rugged, and inexpensive to produce. Yet, the specific interaction of the sensor strip contact region and detector electrodes was never fully explored. In this application, this aspect of the sensor described previously will be addressed.
It is therefore a primary object of the present invention to provide an improved electrical contact between detection unit electrodes and sensor strip in a sensor system that utilizes a method of detection, in which the fluctuations of macromolecular-associated electrostatic fields in proximity to an electrically-conducting base member induce de novo electron motion in the base member; and
It is a further object of the invention to describe an optimal sensor strip-embodiment for electrode contact to allow for rapid detection of analyte.
It is an additional object of the invention to improve the consistency of detection of an analyte in a sensor system.
These and other objects of the present invention are attained by a sensor which has one or a plurality of electrically conductive or semiconductive base members, and at least one macromolecular entity disposed proximate each base member and interactive at a level of specificity with at least one predetermined analyte. Electron motion induced in the conducting portion of the base member is responsive to the interaction of the macromolecular entity with analyte. A detection unit detects the induced electron motion through contact or proximity of associated electrical leads to the base member and/or a conductive or semiconductive layer proximate each base member.
Optionally a self-assembled monolayer (SAM) or other chemical entity is bound to each base member, proximate the macromolecular entity. Macromolecular entities are arranged in a monolayer or multilayer.
According to an aspect of the invention a plurality of macromolecular entities is employed for the detection of at least one analyte.
According to another aspect of the invention electrical leads of the detection unit are coupled to the base member and/or a proximate conductive or semiconductive layer proximate at no more than two positions. The coupling may be passive. The induced electrical signal measured by a detection unit attached to these electrodes, or a component of said signal, may be processed for analyte detection or quantification.
According to yet another aspect of the invention each base member is a conducting foil, coating, thin-film, ink, or solid piece.
According to an additional aspect of the invention, the proximate conductive or semiconductive layer is prepared from organic or inorganic semiconductors
In a further aspect of the invention a packaging layer is disposed above the macromolecular entity, the packaging layer being soluble in a medium that contains the analyte. Electrode contact to sensor strip may be made on the conductive layer formed from macromolecule and packaging layer on the base member.
The invention provides a method for detecting an analyte, having the following steps: providing one or a plurality of electrically conductive base members; immobilizing at least one macromolecule in proximity to at least one side of each base member, wherein the macromolecule is capable of interacting at a level of specificity with a predetermined analyte; depositing a conducting or semiconducting layer proximate the base member, this layer being optionally separated from the base member by other material; contacting leads of a detection unit to said base member and conducting or semiconducting layer; and, detecting induced electron motion in these layers, and signal is responsive to analyte presence.
Optionally a self-assembled monolayer or chemical entity is bound to each base member, the macromolecules are immobilized proximate to the self-assembled monolayer on at least one side of the base member.
According to another aspect of the invention, a plurality of macromolecules having different specificity of interaction with analyte are immobilized for the detection of at least one analyte.
Preferably the step of detecting is performed by coupling electrical leads of a detection unit to the base member and the conductive or semiconductive layer proximate each base member at no more than two positions per sensor strip. The coupling may be passive.
According to yet another aspect of the invention, the macromolecular entities are arranged in a monolayer or multilayer proximate the base member.
According to still another aspect of the invention, a packaging layer is disposed above the macromolecules, the packaging layer being soluble in a medium that contains the analyte. The packaging and macromolecular layers may serve as the conductive or semiconductive layer disposed proximate the base member.
According to an additional aspect of the invention, a further step comprises processing the induced electrical signal or a component thereof for determination of analyte presence or quantity.